Hi.
These are low cost lasers dur to the low duty cycle, i understand that there are a lot of scams on ebay but this is not a scam, as these are genuine 300mw lasers, but as they heat up the power output can lower, as the duty cycle is very low, they can not be kept on for more than ten seconds or the diode will then overheat. I think you are looking for a 300mw laser which is from somewhere lkike wiked lasers which has a longer duty cycle, so therefore i suggest you but from them sas i dont think this laser is what you are looking for.
Regards
Shane